Hi Arnd,

On 2016/1/13 6:51, Arnd Bergmann wrote:

On Tuesday 12 January 2016 17:28:05 xuejiancheng wrote:

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Not yet.
Arnd Bergmann and Rob Herring all suggested adding a specific compatible string
with the SOC name. This binding is just used for describing the compatible string now.
When more functions on hi3519 SOC are added later, the specific driver will be also
needed.

Save this binding until it has more functionality.  We here "I'll add
to this later" all too often.

In the hi3519.dtsi file, there is a system-controller device node described like below:
sysctrl: system-controller@12010000 {
     compatible = "hisilicon,hi3519-sysctrl", "syscon";
     reg = <0x12010000 0x1000>;
};
Do you mean that I should remove "hisilicon,hi3519-sysctrl" and just use "syscon" as the
compatible string?　

Where is this compatible string _used_?

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If I want to add "hisilicon,hi3519-sysctrl" for hi3519. where should I put this binding?
Could you give some suggestions?  Thank you very much!

If you're not using the compatible i.e. the device doesn't have its
own driver yet, then there is no need to supply the binding at all, is
there?

OK. Thank you.

Sorry for stepping in late here. I still think that every syscon device should
come with a specific compatible string, so we have the option of creating a
driver later on, and I'd like to see a binding document that lists those strings
(which I believe exists here).

It's really hard to add compatible strings later on, anything else we can
work around by keying off that string and adding a workaround in the kernel.

Is it OK if I put this binding document into the directory "Documentation/devicetree/bindings/arm/hisilicon"?

Thank you.

	Arnd

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